The disclosures herein relate generally to space frame joint, and more particularly to a method and apparatus for interconnecting tubular frame members by means of a split separable joint.
Separable joints, such as those used in space frame construction are generally a cylindrical hub which includes a plurality of radially directed slots extending axially along the circumferential surface of the hub. The slots have opposed surfaces facing each other which are ribbed. The ribs extend axially along the opposed surfaces.
Tubular frame members are flattened and crimped at their opposed ends. The crimped ends include elongated flat surfaces extending outwardly, or away from each other. The crimped ends are ribbed in a pattern which can be mated into engagement with the ribs in the hub slots. In this manner, each end of a tubular frame member may be slidably inserted into a respective hub slot and several tubular frame members may be connected at one end to a hub slot to form a spider, i.e., a hub having a plurality of tubes extending radially outwardly therefrom, each tube terminating at a free end.
The free end of each tube can be similarly connected to another hub. Thus, a framework of interconnected spiders formed of tubes and hubs can be joined to form a pre-assembled or modular section of a flat roof, a domed roof, a wall, etc., to be joined with other sections to eventually form a complete structure. The structure, once completed, is then covered with a selected cladding which is attached to the structural framework by means of an interfacing cladding support system. The cladding may be fabric, corrugated steel plates, glass, and other selected materials and may include combinations of these materials for architectural design purposes. For example, a domed roof may be clad with steel and may include a pattern of glass panels in a portion of the roof which has an aesthetic effect when viewed from the interior of the structure.
Joining the pre-assembled sections of the framework is difficult and time-consuming. Each section has a periphery including a plurality of hubs. These hubs are connected to their respective section by tube members as mentioned above. When sections are to be joined, additional members of tubing have one end connected to the peripheral hubs of one section, and have their opposite ends connected to the peripheral hubs of an adjoining section. Because the modular sections are often quite large, e.g., 50 feet square, they must be hoisted into their approximate position, suspended by a crane and then a few of the additional members of tubing must be individually and manually aligned with and inserted into the peripheral hubs to stabilize the hoisted section relative to the section of framework to which the hoisted section is being attached. Once stabilized, additional members of tubing are used to complete the interconnection of the hoisted section into the framework.
Due to the large size of the hoisted, suspended section, and the multi-directional movement of the section while suspended in space, manual insertion of the tube ends into the hub slots is labor-intensive and thus costly. This adds undesirable construction time and cost to each job.
Therefore, what is needed is an apparatus and a method of interconnecting space frame sections which overcomes the alignment problems associated with attaching one end of the tube members to a suspended, modular frame section and then attaching the opposite end of the tube members to the framework which is in place, and which can be accomplished in a facilitated manner which reduces alignment and assembly difficulties associated with present construction techniques and thus reduces construction time and cost.